This project is concerned with the study of the mechanism and regulation of fast axonal transport using single, identified neurons in the central nervous system of the marine gastropod mollusc, Aplysia californica. We are studying the kinetics of transport of radioactively labeled membrane glycoproteins to determine whether different types of organelles have different velocities of transport. Second, we are injecting into identified neurons proteins which specifically bind to actin to determine whether that protein is involved in the generation of force for fast transport. Last, we are studying the transport of serotonergic storage vesicles in an identified serotonergic cell to determine whether, and if so how, the amount and composition of material transported to the synapses of the cell are regulated.